Power transmission mineral oil base fluid



United States Patent O 2,982,734 POWER TRANSMISSION MINERAL OIL BASEFLUID Stanley krsprague, East Alton, and Theodore W. Havely, Alton, 11L,assignol's to Shell Oil Company, a corporation of Delaware No Drawing.Filed June 14, 1957, Ser. No. 665,659

3 Claims. (Cl. 252-'7-8) .mechanisms, particularlythe more complicatedautomotive transmissions, fluid-cooled brake mechanisms and the like,oil lubricated Wet clutches, planetary gears and hydraulic controlmechanisms, depend .on adequate cooling and lubricating of theequipment. Rigorous requirements have been set up to qualify fluids forthis service which includes wide temperature stability .at both high andlow temperatures and a low pour point to insure proper purnpability andfluidity at low temperatures. The fluids must not have a detrimentaleffect on parts with which they come in contact, such as metal surfaces,e.g., copper, and solid non-metallic surfaces, such as organic resinsand the like. They must possess excellent :antifrictional and, in somecases extreme pressure characteristics, to afford proper lubrication ofgears, clutch plates and other parts of the mechanism in which theyareused, such as automotive equipment. Also the fluids must not causechattering, squawking, squealing or produce other noises caused by thefrictionalyvibra tions and/or stick-slip phenomenon of clutch plates orother parts of -;such mechanisms.

The prior .art discloses various functional or power transmission fluidsof the mineral oil or synthetic oil type (organic esters and polyethers)containing as the improving agents various organic phosphates, fattyacids and their esters, halogenated compounds, polymers suchaspolyacrylates and the like. Compositions of this type are objectionablebecause of their inability to eliminate chattering and noises caused byfrictional vibrations like, particularly in equipment whichissubjectedto high speeds and temperatures.

, the above purpose in small amounts of from about 0.01

Patented May 2, 1961 phosphate, distearyl acid phosphate, dibehenyl acidphos phate, distearyl acid phosphate, dioleyl acid phosphate, lauryldiacid phosphate, stearyl diacid phosphate, behenyl diacid phosphate,oleyl diacid phosphate, and mixtures thereof such as mono and dilaurylacid phosphate, mono and distearyl acid phosphate, mono and distearylacid phosphate and the like.

In addition to the above two essential additives and mixtures thereof itis preferred to use in such compositions small amounts of from about0.01% to about 1%- of phenolic, amine and/or metal thiophosphateantioxidants such as alkyl phenols, e.g., diand trialkyl phenols, forinstance 2,4-,,2,3-, 3,4-, 2,;6- and '3,5-diamyl phenol,2,4-dimethyl-6-tertbutyl phenol, 2,6-ditertbutyl- 4-methyl phenol;arylamines such as phenyl-a-naphthylamine orphenyl-fl-naphthyl-amine;metal thiophosphates such as calcium or zincdimethyl cyclohexyldithiophosphate anti-foaming agent e.g., siliconepolymers (DC 200 fluids ranging in viscosity in centistokes from 100to1000 at 250 C.) or s'il-icone-t-ype A fluid made by Dow- Corning Co.-anddescribed in US. Patents 2,563,588 and 2,662,055 and mixtures thereof.

As stated above the base oils are hydrocarbon oils of wide viscosityrange. Such .oils have a viscosity in the range of 40 S'US at'100 F. to150 SUS at 210 F. and

are illustrated by mineral oils which include mineral spirits, mineralseal oil, mineral spray oil transformer oil and/or stick-slip phenomenonof clutch plates and the:

GR API 31.2 ColorASTM 1 Pour point a --30 Flash, F. r 270 Fire, F. l 29SViscosity SUS at 100' F. I I '48 Viscosity index 33' to about 5%,preferably from about 0.1% to about 1%, i

by weight, in a hydrocarbon oil of wide viscosity range! The agents arerespectively saturated fattyacids having from 18 to 30 carbon atoms andpreferably saturated 3 fattyacids having fron 18 to 26 carbon. atoms,such as stearic acid and cerotic acidand monoorfdi-aliphafic acidphosphates such as monoor (ii-saturated or: unsaturated alkylacidphosphates e.g., mono-or di-alkyl .least'9carbonatoms and7preferablyat leastfl8z' and up I {acid phosphate, or monoa r di-alken ylphosphates or lmixtures thereof, said alkyl or alke'nyl radicals-havingat p J a v miMondhehnyl diacid to 3 6 oarbonatoms in theqaliphaticgroup-Examples of Stearic acid Mineraloil (A as well as lubricating oils,havingSAE numbers of'from SAE 10 to 'SAE 50. Illustrative oils of thistype have the following properties;

SAE 10 MINERAL OIL I Another suitable .base oil is a higbly refinedtraitsformer oil (A). having'the following properties:

7 Still another suitable base oil is a refined oil (B) having thefollowing properties invention?" p 1 r composition A The followingcompositions are illustrative off the Monostearyl diacid phosphate L.

Weightpercent Balance Weight percent Composition C Weight percent 2Monolauryl diacid phosphate Stearic acid 0.2

Mineral oil (B) Balance Composition D Weight percent Monolanryl acidphosphate 0.1 Stearic acid 0.2

Mineral oil (SAE 10) Balance Composition E p Weight percent Mixture ofmono and dilauryl acid phosphate .0.1 Stearic acid 0.2 Mineral oil (B)Balance Composition F 7 Weight percent Monostearyl diacid phosphate 0.1Stearic acid 0.2 2,6-ditertbutyl-4-methyl phenol 0.2Phenyl-u-naphthylamine 0.1 Mineral oil (B) Balance Composition G Weightpercent Monobehenyl diacid phosphate 0.1 Cerotic acid 0.2 Mineral oil(SAE 10) Balance Composition H a Weight percent Mono-oleyl diacidphosphate Stearic acid 0.2

2,6-ditertbutyl-4-methyl phenol 0.2

Phenol-u-naphthylamine 0. 1 D-C 200 'Fluid (1000 cs. at 25 C.) 5 ppm.

Mineral oil (A) Balance *D-CQOO F1nid=dimethyl silicone polymer. i

l; The superioritybf compositions of this invention, to eliminate noise,frictional vibrations and stick-slip sliding inliquid cooled hydraulicbrake systems in which the parts were'made of steel and resilient, or.semi-metallic, or full sintered metallic friction materials wereevaluated in-actualautomobile tests wherein the noise created afteraccelerating and suddenly stopping the vehicle wasrated,

10 being excellent, no noise or stick-slip and 'zero (0) being poor,severe noise and stick-slip.

With compositions A, B, C, D, E, F, G and H the ratings were between 8and 10. Mineral oils (A) or (B) each containing 0.2% stearic acid or0.2% cerotic acid gave ratings of 4 and 5 respectively. Mineral oil (A)or (B) each containing 0.5% .of n-octyl acid phosphate, dioctyl acidphosphate and triisooctyl phosphate, g'ave ratings of 4,1 and 1respectively, while mineral oil (A) containing 0.4% lauryl acidphosphate gave a rating of 3.

Additives of this invention are useful in various functional fluidswhich contain minor amounts of other agents such as viscosity indeximprovers, point depressants, corrosion inhibitors and the like.

We claim as our invention: I I

1. A power transmission fluid consisting essentially of a major amountof mineral oil containingfrom about 0.1% to about 1% stearic acid,-fromabout 0.01% toabout 1% ditertbutyl4-methylphenol, from about 0.01% toabout 1% phenyl-alpha-naphthylamine and from about 0.1% to about 1% ofdiacid phosphate selectedfrom the group consisting of monooleyl diacidphosphate and monostearyl diacid phosphate.

2. A power transmission fluid consisting essentially of. a major amountof mineral lubricating oil and containing 0.2% stearic acid, 0.3%mono-oleyl diacid phosphate, 0.2% 2,6-ditertbutyl-4-methyl phenol and0.1% phenyla-naphthylamine.

3. A power transmission fluid consisting essentially ofi a major amountof mineral lubricating oil and containing 0.2% stearic acid, 0.3%monostearyl diacid phosphate, 0.2% 2,6-ditertbuty1-4-methyl phenol and0.1% phenyla-naphthylamine.

References Cited in the file of this patent UNITED STATES PATENTS2,005,619- Graves June '18, 1935 2,080,299 Benning May 11,19372,203,'102 -';Powers June 4, 1940 2,447,483, v Baker Aug. 24,19482,686,760 Watson .4 Aug. 17,1954 2,687,377 'Stewart Aug. 24, 19542,694,045 Jones Novj9, 1954 2,779,739; Spivak Jan: 29', 957 2,830,956'Wasson et'al. Apr, 15,1958 2,913,415

1. A POWER TRANSMISSION FLUID CONSISTING ESSENTIALLY OF A MAJOR AMOUNTOF MINERAL OIL CONTAINING FROM ABOUT 0.1% TO ABOUT 1% STEARIC ACID, FROMABOUT 0.01% TO ABOUT 1% DITERTBUTYL-4-METHYLPHENOL, FROM ABOUT 0.01% TOABOUT 1% PHENYL-ALPHA-NAPHTHYLAMINE AND FROM ABOUT 0.1% TO ABOUT 1% OFDIACID PHOSPHATE SELECTED FROM THE GROUP CONSISTING OF MONOOLEYL DIACIDPHOSPHATE AND MONOSTEARYL DIACID PHOSPHATE.